Truck illuminating lamps



March 5, 1963 F. E. KEMP 3,08

TRUCK ILLUMINATING LAMPS Filed Aug. 5, 1960 I N VEN TOR.

@5144, w /Z/w Unit My invention relates to trucks which are loaded andunloaded on freight docks, and more particularly to the lamps employedfor illuminating the interior of the trucks. This type of lamp iscarried by a cord which leads from the ceiling of the dock. When therear doors of the truck have been opened, the conventional lamp ishooked or otherwise temporarily attached over the entrance, so that theinterior of the truck is illuminated while loading or unloading is goingon. However, at times the driver of the truck forgets to detach the lampwhen he drives away from the dock, in which event the cord is broken andthe lamp is carried away by the truck.

In view of the above disadvantage, it is one object of the presentinvention to provide a lamp which becomes detached from the truckautomatically and without damatent age or other impairment in case thetruck is driven away from the dock while carrying the lamp.

A further object is to employ a magnetic mounting device for the lampwhich is attachable to the top of the truck over the rear entrance bysimple application.

Another object is to employ an electromagnet as the attaching device forthe lamp, and include the electromagnet in the Wiring circuit of thelamp. I

An additional object is to provide a holder for the lamp whichincorporates a switch in the electromagnet circuit and means to open theswitch and extinguish the lamp in case the truck departs from the dockand pulls on the cord, the electromagnet releasing its hold in suchevent and causing the lamp to drop away from the truck.

Another object is to construct the novel lamp as a compact unit, andalong lines of simplicity.

A better understanding of the invention may be gained by reference tothe accompanying drawing, in which FIG. 1 is a fragmental rear view ofthe truck body, showing the lamp attached to the same;

FIG. 2 is a section on the line 22 of FIG. 1;

FIG. 3 is an enlarged section on the line 33 of FIG. 2, showing theswitch open;

FIG. 4 is a view similar to FIG. 3, showing the switch closed; and

FIGS. 5 and 6 are, respectively, sections on the lines 55 and 66 of FIG.3.

Referring specifically to the drawings, 10 denotes a typical truck body,with side doors 11 hinged to the same at 12 and shown folded back. Themetallic rear edge of the body top is indicated at 13.

The ceiling or overhead support of the dock in which the truck is loadedor unloaded is indicated at 15, with an electric outlet fixture 17installed. A cord 13 depends from the fixture to terminate with theusual lamp designed to provide illumination for the interior of thetruck while it is in the dock. When the lamp is not in use, it simplyhangs from the fixture to a point where it may be reached from the rearof the truck.

For the present purpose the cord 18 does not lead to the lamp directly,but through the intermediary of a lamp holder or attaching unit 20.Primarily this unit is in the form of a horizontally-positionabletubular housing made in lower and upper halves 20 and 21 which aresecured together by side lugs 22, bolted at 23. The housing carries apendent vertical spool 25, having an end flange indicated at 25a; andthe cord-if found too long-is designed to be wrapped around the spoolbefore entering the housing 20, as shown in FIGS. 1 and 3. FIGS. 2 and 4show that a bracket 27 extends laterally from the lower end of 3,080,477Patented Mar. 5, 1963 the spool 25 into the truck interior, the bracketcarrying the lamp 30. A passage is provided through the spool andbracket for a cord 32 which supplies electric current to the lamp.

The housing 20 contains a switch interposed between the cords 18 and 32.Thus, one terminal of this switch receives the feed wires 18a of thecord 18 in the contact posts 35a of a companion pair of curved blades35. These bear against an insulation block 37 which is slidable in therear end of the housing 20, the inner end of the block having hollows37a to seat the blades, and a partition 37b to separate them. The blockalso has longitudinal top and bottom grooves 370 receiving housing ribs20a for sliding guidance and to keep the block from turning.

In the forward end portion of the housing is lodged a partition disc 40extended with a central boss 40a. To the latter are applied the endportions of a companion pair of spring loops 42 which are inregistration with the curved blades 35. Thus, when the block 37 ispushed inwardly, it will arch the blades until they meet the loops 42;and the further advance of the block will Wrap the blades over the loopsand compress the latter to the bulging form illustrated in FIG. 4.

Before the cord enters the housing 20, it descends through a keeper 45behind the switch block 37. The latter has a latch 47 hingedhorizontally at 47a and poised apart from the cord 18 when the lamp isnot in use and the switch block 37 is in the backed position indicatedin FIG. 3; and the tension of the blades 35 normally maintains theswitch block in the backed position, which is an indication that theswitch is open.

When the device is to be applied to a truck, the first concern is ofcourse to light the lamp. To do this, the latch 47 is swung down to thehorizontal position indicated in FIG. 4. The length of the latch firstcauses it to bear rearwardly on the cord 18 and seat the same firmly inthe rear end of a keeper 45; and the action of the latch also causes itto bear forwardly on the switch block 37, to the extent of closing theswitch as shown in FIG. 4. The switch connects with the wires 32a of thecord 32 by way of the terminals 42a of the loops 42, and the lamptherefore becomes lighted by the action just described.

The housing carries an electromagnet 50 in its front end, the core 50aof which may project as shown. The terminals of the electromagnet areshown at 5612, and connection between them and the terminals 42a is madeby spring contact strips 52 carried by the disc 40, or other suitablemeans, whereby to include the electromagnet in the lamp circuit. Now thedevice is ready for application with the electromagnet core Sila to themetallic top edge 13 of the truck as indicated in FIG. 2, so that thelamp is supported to illuminate the interior of the truck.

When the work in the truck is ended, it is only necessary to open thelatch d7 in order to extinguish the lamp and de-energize theelectromagnet. The device will now drop away from the truck and remainsuspended from the fixture 17 until its use is again required. However,should the driver or truck attendant neglect to open the latch, butdrive off with the truck, the pull on the cord 18 will be upward inrelation to the latch 47 and keeper 45, so that the cord will open thelatch. The relaxation of the blades 35 will now open the switch in thehousing 20, causing the lamp to become extinguished and theelectromagnet to release its hold, so that the device drops away fromthe truck to the suspended or idle position mentioned.

By making the housing in upper and lower halves, it will be possible toassemble its contents with facility; and the disc 40 and electromagnet50 may be locked in place by being formed with peripheral pockets 40cand 500 which receive lugs 29d carried by the walls of the housing.

t will now be apparent that the present device accomplishes the mountingof the lamp in the truck with an v spe s77 automatic detaching factor.Normally, the device would be detached manually when the truck is aboutto be driven away; or, where it is necessary to close the doors of thetruck before leaving, the position of the device is an obstacle. to theclosing of the doors and therefore dictates the. manual removal of thedevice before the doors are closed. However, where the truck has beenemptied or has few contents, the closing of the doors may be consideredunnecessary and the removal of the device neglected or overlooked, inwhich event the automatic detaching feature would accomplish the removalof the device and the extinguishing of the lamp withoutda-mage to orloss of any part. The cord 18 should be made of ample length in case thetruck is located at 'a distance from the outlet fixture 17. However,where the truck is nearby or directly underneath, the slack in the cordmay be taken up by wrapping it on the spool 25, so that no part of thecord will hang in back of the truck entrance to be inthe way. Further,the exposed position of the devce andits liability to impact with thetruck or objects being moved in, or out of the same would disqualify theuse of a conventional switch, whereas a strong pressing and wrappingengagement is secured in the present switch which should enable it towithstand shocks and vibration; and the fully enclosed position of theswitch should protect it against corrosion from climatic conditions.

While I have described the invention alongspecific lines, various minorchanges or refinements may be made therein without departing from itsprinciple, and I reservethe right to employ all such changes andrefinements as may come within the scope and spirit of the appendedclaims.

I claim:

1. An automaticallyoperating switch-and-lamp holder foruse'on amagnetically atractive support surface comprising in combinationanelectric current conducting cord; a hollow housing; said housingincluding electromagnet means for engagement on' said magneticallyattractive support surface; said housing including cordsaid cord; saidhousing including therein a normallyopen switch, said switch including afirst contact means electrically connected to said electromagnet means;an electrically energized lamp carried by said housing and electricallyconnected to said first contact means for simultaneous energization withsaid electromagnet means; said switch including a switch blockdisplaceably supported in said housing in opposition to said cord-keepermeans; said switch including a biasing-contact means electricallyconnected to said cord and normally spaced from said first contact meansengaging said switch block and normally urging the block toward saidcord-keeper means; said switch block including a latch movably mountedthereon and clampingly engageable with saidcord adjacentand against saidcord-keeper means in opposition to said biasing-contact means for urgingsaidblock and biasing-contact means toward said first contact means forclosing a circuit therebetween and simultaneously energizing saidelectromagnet means and said lamp.

2. The structure of claim 1 wherein said housing includes a dependingspool and bracket supporting said lamp, said lamp electrical connectionincluding a current conductor threaded in said spool and bracket andelectrically connected to said first contact means.

keeper means extending about an intermediate portion of 3. The structureof claim 1 wherein said first contact means comprises a U-shaped leafspring extending toward said switch block, said biasing-contact meanscomprising an arcuate leafspring disposed in confronting relation tosaid U-shaped leaf spring, said switch block including an arcuate grooveslidably receiving said arcuate leaf spring. 7 s

4. The structure of claim lwherein said latch comprises a leverpivotally mounted on said switch block.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN AUTOMATICALLY OPERATING SWITCH-AND-LAMP HOLDER FOR USE ON AMAGNETICALLY ATRACTIVE SUPPORT SURFACE COMPRISING IN COMBINATION ANELECTRIC CURRENT CONDUCTING CORD; A HOLLOW HOUSING; SAID HOUSINGINCLUDING ELECTROMAGNET MEANS FOR ENGAGEMENT ON SAID MAGNETICALLYATTRACTIVE SUPPORT SURFACE; SAID HOUSING INCLUDING CORDKEEPER MEANSEXTENDING ABOUT AN INTERMEDIATE PORTION OF SAID CORD; SAID HOUSINGINCLUDING THEREIN A NORMALLY OPEN SWITCH, SAID SWITCH INCLUDING A FIRSTCONTACT MEANS ELECTRICALLY CONNECTED TO SAID ELECTROMAGNET MEANS; ANELECTRICALLY ENERGIZED LAMP CARRIED BY SAID HOUSING AND ELECTRICALLYCONNECTED TO SAID FIRST CONTACT MEANS FOR SIMULTANEOUS ENERGIZATION WITHSAID ELECTROMAGNET MEANS; SAID SWITCH INCLUDING A SWITCH BLOCKDISPLACEABLY SUPPORTED IN SAID HOUSING IN OPPOSITION TO SAID CORD-KEEPERMEANS; SAID SWITCH INCLUDING A BIASING-CONTACT MEANS ELECTRICALLYCONNECTED TO SAID CORD AND NORMALLY SPACED FROM SAID FIRST CONTACT MEANSENGAGING SAID SWITCH BLOCK AND NORMALLY URGING THE BLOCK TOWARD SAIDCORD-KEEPER MEANS; SAID SWITCH BLOCK INCLUDING A LATCH MOVABLY MOUNTEDTHEREON AND CLAMPINGLY ENGAGEABLE WITH SAID CORD ADJACENT AND AGAINSTSAID CORD-KEEPER MEANS IN OPPOSITION TO SAID BIASING-CONTACT MEANS FORURGING SAID BLOCK AND BIASING-CONTACT MEANS TOWARD SAID FIRST CONTACTMEANS FOR CLOSING A CIRCUIT THEREBETWEEN AND SIMULTANEOUSLY ENERGIZINGSAID ELECTROMAGNET MEANS AND SAID LAMP.